Examples of a conventional method for producing a 3D facial animation include a manual method using a special modeler, an example-based method, and a method using a facial motion capture system. The manual method by a special modeler is a method producing a facial expression by controlling each vertex of a 3D facial mesh. The example-based method makes in advance 3D models of various facial expressions for a facial animation to be produced and produces a new expression by a combination of the facial models. The 3D facial model made by this method is called a blend shape. The method using a motion capture system produces a 3D facial animation by applying several tens of optical markers to a performer's face, taking photographs of the performer's face by using a high-speed infrared camera, and tracking 3D movements of the optical makers obtained by the photographing.
In the aforementioned conventional art, the manual method using a special modeler is capable of producing a relatively natural facial animation. However, this manual method has the problems in that the produced facial animation is different depending on the used modeler and a long time is required.
The example-based method has the problem in that the accuracy of the produced facial animation depends on the accuracy of the models which are made in advance and the extent of combinations of the models.
The method using a motion capture system is fast in terms of a work processing speed and is capable of producing a high quality animation. However, this method incurs high costs since it needs an expensive system.